Veritas File System 5.1 SP1 Administrator"s Guide (5900-1499, April 2011)

The MVS feature also allows file systems to reside on different classes of devices,
so that a file system can be supported from both inexpensive disks and from
expensive arrays. Using the MVS administrative interface, you can control which
data goes on which volume types.
See the Veritas Volume Manager Administrator's Guide.
Note: Multi-volume support is available only on file systems using disk layout
Version 6 or later.
See “About disk layouts” on page 231.
About volume types
VxFS utilizes two types of volumes, one of which contains only data, referred to
as dataonly, and the other of which can contain metadata or data, referred to as
metadataok.
Data refers to direct extents, which contain user data, of regular files and named
data streams in a file system.
Metadata refers to all extents that are not regular file or named data stream
extents. This includes certain files that appear to be regular files, but are not, such
as the File Change Log file.
A volume availability flag is set to specify if a volume is dataonly or metadataok.
The volume availability flag can be set, cleared, and listed with the fsvoladm
command.
See the fsvoladm(1M) manual page.
Features implemented using multi-volume support
The following features can be implemented using multi-volume support:
■ Controlling where files are stored can be selected at multiple levels so that
specific files or file hierarchies can be assigned to different volumes. This
functionality is available in the Veritas File System SmartTier feature.
■ Placing the VxFS intent log on its own volume to minimize disk head movement
and thereby increase performance. This functionality can be used to migrate
from the Veritas QuickLog™ feature.
■ Separating Storage Checkpoints so that data allocated to a Storage Checkpoint
is isolated from the rest of the file system.
Multi-volume file systems
About volume types
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